Project Summary/Abstract Barth syndrome (BTHS; OMIM #302060) is a rare, life-threatening, X-linked, multi-system genetic disorder affecting primarily males [1-6]. The cardinal characteristics of this unique mitochondrial disease are dilated cardiomyopathy (sometimes hypertrophic cardiomyopathy), muscle hypoplasia, extreme fatigue/weak- ness, neutropenia, growth delay, and a reduction of tetralinoleoyl cardiolipin (a major phospholipid of the mitochondrial inner membrane). In the first description of Barth syndrome in 1983, Dr. Barth delineated all of the principal clinical findings, established the X-linked mode of inheritance, and described the abnormalities of mitochondrial structure and function in muscle and leukocytes. In 1996 causative mutations for BTHS were found in the gene subsequently designated tafazzin or TAZ, located in the gene-rich Xq28 chromosomal region [7]. In 2000 Dr. Peter Vreken and colleagues discovered that fibroblasts from BTHS patients have essentially absent levels of mitochondrial tetralinoleoyl cardiolipin [8]. Fortunately, this discovery also coincided with the incorporation of the Barth Syndrome Foundation (BSF) as a non-profit, patient-advocacy group Since its inception BSF has sponsored biennial International Scientific, Medical and Family Confer- ences (hereafter referred to as Conferences) to highlight scientific and clinical advances, to educate patients and their families, to help deal with patient concerns, to promote the advancement of BTHS research and researchers, and to establish a vibrant patient-centered community. These unique Conferences have evolved from simple gatherings of a few families who have sons suffering from this rare disease along with their treating physicians, to International Conferences where important scientific and clinical advancements are presented and new investigators to the field are recruited, encouraged, and supported. The search for therapeutic treatments or compounds is always a major focus of these Conferences, though it is only recently that clinical therapies have been able to be discussed in any detail. At the 2018 Conference we will hear reports from the first pharmaceutical BTHS clinical trials?the TAZPOWER trial in the US and the CARDIOMAN trial in the UK. Preclinical data regarding an anticipated gene therapy trial will also be presented. Up to now only palliative care is available to BTHS individuals, but through BSF and these biennial Conferences real ?bench to bedside? stories are being told. These Conferences are the only forums where therapies and therapeutic ideas can be effectively presented, discussed, critically evaluated, and acted upon, not only by the researchers and physicians directly involved, but also by the affected individuals and their families. These Conferences add value to science and medicine and provide real hope to BTHS individuals.